Evaluating Growth and Physiological Responses of a Medicinal Plant Phyla nodiflora to Salinity

Abstract

Phyla nodiflora is a valuable medicinal plant growing in coastal areas, hypothesizing its adaptability to salinity; however, it has not been investigated. This study, for the first time, elucidated responses in the growth of the shoots and its physiology to different soil salinity of 50–400 mM NaCl. The data showed that the shoot’s dry biomass was not affected by the salinity levels up to 100 mM, and it only decreased 33.50–56.33% compared to the control under 200–400 mM NaCl, indicating that P. nodiflora is a salt-tolerant plant that could survive under high salinity. In addition, the plant also had physiological responses which indicated its salt-induced injuries and adaptation to the salt stress. The chlorophyll a content was increased while the chlorophyll b remained unchanged under the salt stress. The proline and salt accumulation increased under the salinity, but the K+ and NO3− accumulation decreased. Moreover, increases in malondialdehyde and electrolyte leakage were observed, indicating salt-induced membrane damages. These responses suggested that the plant might evolve adaptive mechanisms to salinity. Our findings are useful information for further research in order to elucidate the salt-tolerant mechanisms and develop this plant for saline agriculture.